1. Field of the Invention
This invention relates to multiple product dispensing containers, such as dual dispense containers, comprised of an outer container and an inner container, wherein products contained in the respective inner and outer containers are simultaneously dispensed from the dual dispense container orifice. More particularly, this invention is directed to the securement of inner containers to outer containers of dual dispense containers.
Dual dispense containers, including collapsible dual dispense tubes, are well known. However, there has been a need for a more effective way to secure the inner and outer containers of dual dispense containers such that, once assembled, they will be locked together and will not move axially or laterally relative to one another. A mere friction fit between the necks of the inner and outer containers, for example, tubes, has not been effective. Providing interengaging portions, e.g., protrusions and indentations at the middle to upper portions of the respective inner and outer tube necks has been somewhat effective in providing less axial movement between the inner and outer tubes, but this approach has not eliminated relative axial or lateral movement, and it has posed problems in manufacturing and assembling the respective tubes. The approach has presented manufacturing problems because once the particular neck is molded with such an upper protrusion, the neck must be moved a relatively long distance along the mold tooling to remove the neck from the tooling. This causes shearing of a portion of the protrusion, and/or distortion or deformation of the tube neck. The distortion or deformation can be permanent or can weaken the neck wall of the tube such that, the inner and outer tube necks, once assembled, may not fit tightly one within the other. This may cause disengagement and/or axial movement of the protrusion relative to its indentation, leakage, and/or an alteration in the product dispense ratios designed for the dual dispense tube.
Providing protrusions at the middle to upper portions of the tube neck has been problematical during assembly of the inner and outer tubes, because it has required pushing the inner tube neck a relatively long distance into the outer tube neck to seat the protrusion in its indentation. The closer the protrusion is to the neck orifice, the further the inner tube must be pushed, the more wear or shearing there is on or of the protrusion, and the greater the chance of the inner tube neck being inserted too far, such that the protrusion is pushed beyond the orifice of the outer tube. While some prior dual dispense tubes have been provided with sloping shoulder engaging surfaces to prevent this from occurring, such engaging surfaces have not been wholly effective in preventing over-insertion from occurring.
Further, providing interengaging portions at the middle to upper portions of the tube necks can present filling problems. It allows the inner tube to cant or become non-concentric at the bottom open end of the dual dispense tube and thereby cause misalignments with concentric filling heads of filling machines.
2. Description of Related Art
Examples of known dual dispense containers are disclosed in the following patents. U.S. Pat. No. 1,699,532 to Hopkins discloses an inner collapsible tube disposed within an outer collapsible tube. The upper end of the inner tube neck has outwardly extending projecting portions which friction fit within the outer tube neck, and the inner tube shoulder has projections or knots having an edge which engage the downwardly sloping inner surface of the outer tube shoulder at points spatially removed from the base of the outer tube neck. With this construction, the tubes are not locked securely together. There can be relative axial movement between the tubes. For example, the inner tube can be pushed downwardly into the outer tube. Also, during assembly, when the inner tube is pushed into the outer tube, the inner tube neck can be pushed too far such that the inner tube knots can ride up the inclined outer tube shoulder surface and the projecting portions at the upper end of the neck can be pushed beyond the orifice of the outer tube. It has been found that if the dual tube is designed with greater friction between the outer and inner tube necks, the inner tube neck can collapse or be distorted. If the walls of the inner tube neck are thickened to prevent this, the dispense area of the inner tube is reduced and during dispensing, there is an increased pressure drop and less product flow from the inner tube for mixing with product from the outer tube.
U.S. Pat. No. 2,218,092 to Nitardy discloses another collapsible dual dispensing tube wherein the securement of a metal inner tube within a metal outer tube is effected by a mere friction fit between radially outwardly projecting lugs on the inner tube neck and the inner surface of the outer tube neck, and between lower sloping portions of the lugs and the sloping portion of the outer tube under the base of its neck. Again, in this construction, the inner tube neck can move axially within the outer tube neck. For example, the upper tube neck extends beyond the outer tube neck and there is nothing to prevent the inner tube neck from being pushed down into the outer tube neck. Also, the sloping portion of the inner tube neck can ride up on the sloping portion of the outer tube.
U.S. Pat. No. 2,939,610 to Castelli et al discloses a collapsible dual dispensing tube wherein the securement between the inner and outer tubes is effected by a friction fit between opposed portions of the inner tube neck and the outer tube neck. With this construction, although the outer tube neck orifice has a flange which extends radially inwardly over the lip of the inner tube and prevents the inner tube from being pushed further up into the outer tube, the inner tube neck still can move axially down into the outer tube neck. This construction is also undesirable because at the flange of the orifice, there will be an accumulation and premature mixing of inner product and outer product. Also, such mixed product will be pushed into the dual dispense tube neck when the cap is secured into the tube.
U.S. Pat. No. 4,687,663 to Schaeffer discloses a collapsible dual dispense tube whose inner tube neck has opposed outward protrusions which fit in a groove on the inner surface of the outer tube neck. While this construction would prevent axial movement between the tubes, it would not prevent the inner tube neck from being overinserted into the outer tube neck. Also, it would not prevent lateral, rocking or canting movement of the inner tube within the outer tube. This movement could cause filling problems. It could also affect the sizes and shapes of one or both of the respective dispense orifices and of the channels leading to those orifices and could thereby cause the actual product dispense ratio to be different from that designed for the inner and outer tubes.
U.S. Pat. No. 5,328,056 to Schneider et al discloses an improved collapsible dual dispensing tube having an annular fixing rib extending radially inward from the inner surface of the outer tube neck near its orifice, and which is engaged within an annular groove in the outer surface of the inner tube neck. The inner tube also has ribs whose edges abut against the inner surface of sloping shoulders of the outer tube at points spatially removed from the base of the outer tube neck.
Given existing collapsible dual dispense containers as discussed above and as disclosed in the aforementioned patents, it is desirable and it is a primary objective of this invention to provide dual dispense containers, especially collapsible ones, for example, collapsible dual dispense tubes, having improved securement between the inner and outer containers which prevents axial movement and preferably also lateral, canting or rocking movement between the containers.
Another object of this invention is to provide aforementioned desired collapsible dual dispense containers having securement means located at the base of the neck of the outer tube, for securing the inner and outer tubes together.
Another object of this invention is to provide such a desired collapsible dual dispense tube having improved securement means in the form of a bead extending outward from the outer surface of the inner tube neck and which is frictionally engaged within a groove in the inner surface of the outer tube neck, wherein the bead is located at, adjacent or proximate to the base of the neck of the outer container.
Another object of this invention is to provide an aforementioned desired collapsible dual dispense tube whose inner tube has a plurality of locking members disposed about the inner tube neck, whose outer tube neck has an undersurface, and wherein the locking members abut the undersurface and assist in maintaining the bead within the groove.
Yet another object of this invention is to provide an aforementioned collapsible dispense tube whose outer tube has a latch at the base of the outer tube neck below the groove, such that the abutment of the locking means of the inner tube against the undersurface of the outer tube latches and locks the bead of the inner tube in the groove of the outer tube.
Still another object of this invention to provide aforementioned desired dual dispense containers which are easy to manufacture, assemble and fill.